1. Field
This invention relates to riding lawn mowers and, more particularly, to the system for mounting the cutting deck on a rear engine riding mower.
2. Description of the Prior Art
Riding lawn mowers have been available for many years and in a wide variety of configurations, being categorized generally as either rear engine or front engine mowers depending upon the placement of the engine in relation to the driver. Typically, riding mowers have a cutting deck suspended generally between the front and rear wheels, serving as a housing for the blade(s). It is common practice for such mowers to also include a height adjustment mechanism for selectively adjusting the cutting height (i.e., the height of the cutting deck from the ground), and for the cutting deck to be suspended in a manner allowing for such height adjustment while maintaining the cutting deck generally parallel to the ground.
Conventional cutting deck mounting systems include a pair of hinged links securing the cutting deck to the frame of the mower. If the frame is sufficiently rigid the cutting deck will maintain its generally parallel orientation with respect to the ground, even when the mower is operated across an inclined or uneven surface. In order to maintain the parallel orientation of the cutting deck under such circumstances, the frame must be stiff enough to avoid twisting along its longitudinal axis commonly caused when one wheel encounters an elevated surface. If the frame is not stiff enough to resist such twisting, the cutting deck will not tilt sufficiently to accommodate the elevated surface, thereby resulting in a condition known as "scalping" where the grass is unintentionally cut too short in an isolated location. This has been a particular problem with rear engine mowers, since their frames are generally lighter and less resistant to torsional flexing than the frames used for front engine mowers.
Since it is highly desirable to avoid scalping portions of the lawn, frames for rear engine riding mowers must be strengthened in order to withstand the torsional forces which cause twisting. Such a high degree of stiffness, or torsional rigidity, requires the frames to be much heavier and expensive than would be required under ideal circumstances. Accordingly, a need has been recognized for a cutting deck mounting system which enables the cutting deck to tilt when required to avoid scalping the lawn, without necessitating the use of an unusually rigid frame.